From 0d3c703a9d1723c7707e0680019ac8ff5922db42 Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Fri, 29 Apr 2016 17:12:15 -0700
Subject: [PATCH 1/7] ipv6: Cleanup IPv6 tunnel receive path

Some basic changes to make IPv6 tunnel receive path look more like
IPv4 path:
  - Make ip6_tnl_rcv non-static so that GREv6 and others can call it
  - Make ip6_tnl_rcv look like ip_tunnel_rcv
  - Switch to gro_cells_receive
  - Make ip6_tnl_rcv non-static and export it

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/ip6_tunnel.h |   4 +
 net/ipv6/ip6_tunnel.c    | 212 ++++++++++++++++++++++++++-------------
 2 files changed, 146 insertions(+), 70 deletions(-)

diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h
index 499a707765ea6..eab3a9b19ae09 100644
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -42,6 +42,7 @@ struct ip6_tnl {
 	struct __ip6_tnl_parm parms;	/* tunnel configuration parameters */
 	struct flowi fl;	/* flowi template for xmit */
 	struct dst_cache dst_cache;	/* cached dst */
+	struct gro_cells gro_cells;
 
 	int err_count;
 	unsigned long err_time;
@@ -63,6 +64,9 @@ struct ipv6_tlv_tnl_enc_lim {
 
 int ip6_tnl_rcv_ctl(struct ip6_tnl *t, const struct in6_addr *laddr,
 		const struct in6_addr *raddr);
+int ip6_tnl_rcv(struct ip6_tnl *tunnel, struct sk_buff *skb,
+		const struct tnl_ptk_info *tpi, struct metadata_dst *tun_dst,
+		bool log_ecn_error);
 int ip6_tnl_xmit_ctl(struct ip6_tnl *t, const struct in6_addr *laddr,
 		     const struct in6_addr *raddr);
 __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw);
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 1f20345cbc970..94ed065eff7f3 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -238,6 +238,7 @@ static void ip6_dev_free(struct net_device *dev)
 {
 	struct ip6_tnl *t = netdev_priv(dev);
 
+	gro_cells_destroy(&t->gro_cells);
 	dst_cache_destroy(&t->dst_cache);
 	free_percpu(dev->tstats);
 	free_netdev(dev);
@@ -753,97 +754,157 @@ int ip6_tnl_rcv_ctl(struct ip6_tnl *t,
 }
 EXPORT_SYMBOL_GPL(ip6_tnl_rcv_ctl);
 
-/**
- * ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
- *   @skb: received socket buffer
- *   @protocol: ethernet protocol ID
- *   @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN
- *
- * Return: 0
- **/
-
-static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
-		       __u8 ipproto,
-		       int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
-						   const struct ipv6hdr *ipv6h,
-						   struct sk_buff *skb))
+static int __ip6_tnl_rcv(struct ip6_tnl *tunnel, struct sk_buff *skb,
+			 const struct tnl_ptk_info *tpi,
+			 struct metadata_dst *tun_dst,
+			 int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
+						const struct ipv6hdr *ipv6h,
+						struct sk_buff *skb),
+			 bool log_ecn_err)
 {
-	struct ip6_tnl *t;
+	struct pcpu_sw_netstats *tstats;
 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
-	u8 tproto;
 	int err;
 
-	rcu_read_lock();
-	t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
-	if (t) {
-		struct pcpu_sw_netstats *tstats;
+	if ((!(tpi->flags & TUNNEL_CSUM) &&
+	     (tunnel->parms.i_flags & TUNNEL_CSUM)) ||
+	    ((tpi->flags & TUNNEL_CSUM) &&
+	     !(tunnel->parms.i_flags & TUNNEL_CSUM))) {
+		tunnel->dev->stats.rx_crc_errors++;
+		tunnel->dev->stats.rx_errors++;
+		goto drop;
+	}
 
-		tproto = ACCESS_ONCE(t->parms.proto);
-		if (tproto != ipproto && tproto != 0) {
-			rcu_read_unlock();
-			goto discard;
+	if (tunnel->parms.i_flags & TUNNEL_SEQ) {
+		if (!(tpi->flags & TUNNEL_SEQ) ||
+		    (tunnel->i_seqno &&
+		     (s32)(ntohl(tpi->seq) - tunnel->i_seqno) < 0)) {
+			tunnel->dev->stats.rx_fifo_errors++;
+			tunnel->dev->stats.rx_errors++;
+			goto drop;
 		}
+		tunnel->i_seqno = ntohl(tpi->seq) + 1;
+	}
 
-		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
-			rcu_read_unlock();
-			goto discard;
-		}
+	skb->protocol = tpi->proto;
 
-		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
-			t->dev->stats.rx_dropped++;
-			rcu_read_unlock();
-			goto discard;
+	/* Warning: All skb pointers will be invalidated! */
+	if (tunnel->dev->type == ARPHRD_ETHER) {
+		if (!pskb_may_pull(skb, ETH_HLEN)) {
+			tunnel->dev->stats.rx_length_errors++;
+			tunnel->dev->stats.rx_errors++;
+			goto drop;
 		}
-		skb->mac_header = skb->network_header;
-		skb_reset_network_header(skb);
-		skb->protocol = htons(protocol);
-		memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
-
-		__skb_tunnel_rx(skb, t->dev, t->net);
-
-		err = dscp_ecn_decapsulate(t, ipv6h, skb);
-		if (unlikely(err)) {
-			if (log_ecn_error)
-				net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
-						     &ipv6h->saddr,
-						     ipv6_get_dsfield(ipv6h));
-			if (err > 1) {
-				++t->dev->stats.rx_frame_errors;
-				++t->dev->stats.rx_errors;
-				rcu_read_unlock();
-				goto discard;
-			}
+
+		ipv6h = ipv6_hdr(skb);
+		skb->protocol = eth_type_trans(skb, tunnel->dev);
+		skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
+	} else {
+		skb->dev = tunnel->dev;
+	}
+
+	skb_reset_network_header(skb);
+	memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
+
+	__skb_tunnel_rx(skb, tunnel->dev, tunnel->net);
+
+	err = dscp_ecn_decapsulate(tunnel, ipv6h, skb);
+	if (unlikely(err)) {
+		if (log_ecn_err)
+			net_info_ratelimited("non-ECT from %pI6 with DS=%#x\n",
+					     &ipv6h->saddr,
+					     ipv6_get_dsfield(ipv6h));
+		if (err > 1) {
+			++tunnel->dev->stats.rx_frame_errors;
+			++tunnel->dev->stats.rx_errors;
+			goto drop;
 		}
+	}
 
-		tstats = this_cpu_ptr(t->dev->tstats);
-		u64_stats_update_begin(&tstats->syncp);
-		tstats->rx_packets++;
-		tstats->rx_bytes += skb->len;
-		u64_stats_update_end(&tstats->syncp);
+	tstats = this_cpu_ptr(tunnel->dev->tstats);
+	u64_stats_update_begin(&tstats->syncp);
+	tstats->rx_packets++;
+	tstats->rx_bytes += skb->len;
+	u64_stats_update_end(&tstats->syncp);
 
-		netif_rx(skb);
+	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));
 
-		rcu_read_unlock();
-		return 0;
+	gro_cells_receive(&tunnel->gro_cells, skb);
+	return 0;
+
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+int ip6_tnl_rcv(struct ip6_tnl *t, struct sk_buff *skb,
+		const struct tnl_ptk_info *tpi,
+		struct metadata_dst *tun_dst,
+		bool log_ecn_err)
+{
+	return __ip6_tnl_rcv(t, skb, tpi, NULL, ip6ip6_dscp_ecn_decapsulate,
+			     log_ecn_err);
+}
+EXPORT_SYMBOL(ip6_tnl_rcv);
+
+static const struct tnl_ptk_info tpi_v6 = {
+	/* no tunnel info required for ipxip6. */
+	.proto = htons(ETH_P_IPV6),
+};
+
+static const struct tnl_ptk_info tpi_v4 = {
+	/* no tunnel info required for ipxip6. */
+	.proto = htons(ETH_P_IP),
+};
+
+static int ipxip6_rcv(struct sk_buff *skb, u8 ipproto,
+		      const struct tnl_ptk_info *tpi,
+		      int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
+						  const struct ipv6hdr *ipv6h,
+						  struct sk_buff *skb))
+{
+	struct ip6_tnl *t;
+	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	int ret = -1;
+
+	rcu_read_lock();
+	t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
+
+	if (t) {
+		u8 tproto = ACCESS_ONCE(t->parms.proto);
+
+		if (tproto != ipproto && tproto != 0)
+			goto drop;
+		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
+			goto drop;
+		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr))
+			goto drop;
+		if (iptunnel_pull_header(skb, 0, tpi->proto, false))
+			goto drop;
+		ret = __ip6_tnl_rcv(t, skb, tpi, NULL, dscp_ecn_decapsulate,
+				    log_ecn_error);
 	}
+
 	rcu_read_unlock();
-	return 1;
 
-discard:
+	return ret;
+
+drop:
+	rcu_read_unlock();
 	kfree_skb(skb);
 	return 0;
 }
 
 static int ip4ip6_rcv(struct sk_buff *skb)
 {
-	return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP,
-			   ip4ip6_dscp_ecn_decapsulate);
+	return ipxip6_rcv(skb, IPPROTO_IP, &tpi_v4,
+			  ip4ip6_dscp_ecn_decapsulate);
 }
 
 static int ip6ip6_rcv(struct sk_buff *skb)
 {
-	return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6,
-			   ip6ip6_dscp_ecn_decapsulate);
+	return ipxip6_rcv(skb, IPPROTO_IPV6, &tpi_v6,
+			  ip6ip6_dscp_ecn_decapsulate);
 }
 
 struct ipv6_tel_txoption {
@@ -1370,6 +1431,8 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	struct net *net = t->net;
 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
 
+	memset(&p1, 0, sizeof(p1));
+
 	switch (cmd) {
 	case SIOCGETTUNNEL:
 		if (dev == ip6n->fb_tnl_dev) {
@@ -1549,13 +1612,22 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
 		return -ENOMEM;
 
 	ret = dst_cache_init(&t->dst_cache, GFP_KERNEL);
-	if (ret) {
-		free_percpu(dev->tstats);
-		dev->tstats = NULL;
-		return ret;
-	}
+	if (ret)
+		goto free_stats;
+
+	ret = gro_cells_init(&t->gro_cells, dev);
+	if (ret)
+		goto destroy_dst;
 
 	return 0;
+
+destroy_dst:
+	dst_cache_destroy(&t->dst_cache);
+free_stats:
+	free_percpu(dev->tstats);
+	dev->tstats = NULL;
+
+	return ret;
 }
 
 /**

From 95f5c64c3c13a609e137d35c4b452519e0b954df Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Fri, 29 Apr 2016 17:12:16 -0700
Subject: [PATCH 2/7] gre: Move utility functions to common headers

Several of the GRE functions defined in net/ipv4/ip_gre.c are usable
for IPv6 GRE implementation (that is they are protocol agnostic).

These include:
  - GRE flag handling functions are move to gre.h
  - GRE build_header is moved to gre.h and renamed gre_build_header
  - parse_gre_header is moved to gre_demux.c and renamed gre_parse_header
  - iptunnel_pull_header is taken out of gre_parse_header. This is now
    done by caller. The header length is returned from gre_parse_header
    in an int* argument.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/gre.h    |  60 +++++++++++++++++
 net/ipv4/gre_demux.c |  64 +++++++++++++++++++
 net/ipv4/ip_gre.c    | 149 ++++++-------------------------------------
 3 files changed, 144 insertions(+), 129 deletions(-)

diff --git a/include/net/gre.h b/include/net/gre.h
index 97eafdc47eea1..39591584ec92b 100644
--- a/include/net/gre.h
+++ b/include/net/gre.h
@@ -25,4 +25,64 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version);
 
 struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
 				       u8 name_assign_type);
+int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
+		     bool *csum_err, int *hdr_len);
+
+static inline int gre_calc_hlen(__be16 o_flags)
+{
+	int addend = 4;
+
+	if (o_flags & TUNNEL_CSUM)
+		addend += 4;
+	if (o_flags & TUNNEL_KEY)
+		addend += 4;
+	if (o_flags & TUNNEL_SEQ)
+		addend += 4;
+	return addend;
+}
+
+static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
+{
+	__be16 tflags = 0;
+
+	if (flags & GRE_CSUM)
+		tflags |= TUNNEL_CSUM;
+	if (flags & GRE_ROUTING)
+		tflags |= TUNNEL_ROUTING;
+	if (flags & GRE_KEY)
+		tflags |= TUNNEL_KEY;
+	if (flags & GRE_SEQ)
+		tflags |= TUNNEL_SEQ;
+	if (flags & GRE_STRICT)
+		tflags |= TUNNEL_STRICT;
+	if (flags & GRE_REC)
+		tflags |= TUNNEL_REC;
+	if (flags & GRE_VERSION)
+		tflags |= TUNNEL_VERSION;
+
+	return tflags;
+}
+
+static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
+{
+	__be16 flags = 0;
+
+	if (tflags & TUNNEL_CSUM)
+		flags |= GRE_CSUM;
+	if (tflags & TUNNEL_ROUTING)
+		flags |= GRE_ROUTING;
+	if (tflags & TUNNEL_KEY)
+		flags |= GRE_KEY;
+	if (tflags & TUNNEL_SEQ)
+		flags |= GRE_SEQ;
+	if (tflags & TUNNEL_STRICT)
+		flags |= GRE_STRICT;
+	if (tflags & TUNNEL_REC)
+		flags |= GRE_REC;
+	if (tflags & TUNNEL_VERSION)
+		flags |= GRE_VERSION;
+
+	return flags;
+}
+
 #endif
diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index d9c552a721fcb..371674801e84e 100644
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -60,6 +60,70 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version)
 }
 EXPORT_SYMBOL_GPL(gre_del_protocol);
 
+int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
+		     bool *csum_err, int *ret_hdr_len)
+{
+	const struct gre_base_hdr *greh;
+	__be32 *options;
+	int hdr_len;
+
+	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
+		return -EINVAL;
+
+	greh = (struct gre_base_hdr *)skb_transport_header(skb);
+	if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
+		return -EINVAL;
+
+	tpi->flags = gre_flags_to_tnl_flags(greh->flags);
+	hdr_len = gre_calc_hlen(tpi->flags);
+
+	if (!pskb_may_pull(skb, hdr_len))
+		return -EINVAL;
+
+	greh = (struct gre_base_hdr *)skb_transport_header(skb);
+	tpi->proto = greh->protocol;
+
+	options = (__be32 *)(greh + 1);
+	if (greh->flags & GRE_CSUM) {
+		if (skb_checksum_simple_validate(skb)) {
+			*csum_err = true;
+			return -EINVAL;
+		}
+
+		skb_checksum_try_convert(skb, IPPROTO_GRE, 0,
+					 null_compute_pseudo);
+		options++;
+	}
+
+	if (greh->flags & GRE_KEY) {
+		tpi->key = *options;
+		options++;
+	} else {
+		tpi->key = 0;
+	}
+	if (unlikely(greh->flags & GRE_SEQ)) {
+		tpi->seq = *options;
+		options++;
+	} else {
+		tpi->seq = 0;
+	}
+	/* WCCP version 1 and 2 protocol decoding.
+	 * - Change protocol to IP
+	 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
+	 */
+	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
+		tpi->proto = htons(ETH_P_IP);
+		if ((*(u8 *)options & 0xF0) != 0x40) {
+			hdr_len += 4;
+			if (!pskb_may_pull(skb, hdr_len))
+				return -EINVAL;
+		}
+	}
+	*ret_hdr_len = hdr_len;
+	return 0;
+}
+EXPORT_SYMBOL(gre_parse_header);
+
 static int gre_rcv(struct sk_buff *skb)
 {
 	const struct gre_protocol *proto;
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index eedd829a2f877..f6db3d6a4d4da 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -122,125 +122,6 @@ static int ipgre_tunnel_init(struct net_device *dev);
 static int ipgre_net_id __read_mostly;
 static int gre_tap_net_id __read_mostly;
 
-static int ip_gre_calc_hlen(__be16 o_flags)
-{
-	int addend = 4;
-
-	if (o_flags & TUNNEL_CSUM)
-		addend += 4;
-	if (o_flags & TUNNEL_KEY)
-		addend += 4;
-	if (o_flags & TUNNEL_SEQ)
-		addend += 4;
-	return addend;
-}
-
-static __be16 gre_flags_to_tnl_flags(__be16 flags)
-{
-	__be16 tflags = 0;
-
-	if (flags & GRE_CSUM)
-		tflags |= TUNNEL_CSUM;
-	if (flags & GRE_ROUTING)
-		tflags |= TUNNEL_ROUTING;
-	if (flags & GRE_KEY)
-		tflags |= TUNNEL_KEY;
-	if (flags & GRE_SEQ)
-		tflags |= TUNNEL_SEQ;
-	if (flags & GRE_STRICT)
-		tflags |= TUNNEL_STRICT;
-	if (flags & GRE_REC)
-		tflags |= TUNNEL_REC;
-	if (flags & GRE_VERSION)
-		tflags |= TUNNEL_VERSION;
-
-	return tflags;
-}
-
-static __be16 tnl_flags_to_gre_flags(__be16 tflags)
-{
-	__be16 flags = 0;
-
-	if (tflags & TUNNEL_CSUM)
-		flags |= GRE_CSUM;
-	if (tflags & TUNNEL_ROUTING)
-		flags |= GRE_ROUTING;
-	if (tflags & TUNNEL_KEY)
-		flags |= GRE_KEY;
-	if (tflags & TUNNEL_SEQ)
-		flags |= GRE_SEQ;
-	if (tflags & TUNNEL_STRICT)
-		flags |= GRE_STRICT;
-	if (tflags & TUNNEL_REC)
-		flags |= GRE_REC;
-	if (tflags & TUNNEL_VERSION)
-		flags |= GRE_VERSION;
-
-	return flags;
-}
-
-static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
-			    bool *csum_err)
-{
-	const struct gre_base_hdr *greh;
-	__be32 *options;
-	int hdr_len;
-
-	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
-		return -EINVAL;
-
-	greh = (struct gre_base_hdr *)skb_transport_header(skb);
-	if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
-		return -EINVAL;
-
-	tpi->flags = gre_flags_to_tnl_flags(greh->flags);
-	hdr_len = ip_gre_calc_hlen(tpi->flags);
-
-	if (!pskb_may_pull(skb, hdr_len))
-		return -EINVAL;
-
-	greh = (struct gre_base_hdr *)skb_transport_header(skb);
-	tpi->proto = greh->protocol;
-
-	options = (__be32 *)(greh + 1);
-	if (greh->flags & GRE_CSUM) {
-		if (skb_checksum_simple_validate(skb)) {
-			*csum_err = true;
-			return -EINVAL;
-		}
-
-		skb_checksum_try_convert(skb, IPPROTO_GRE, 0,
-					 null_compute_pseudo);
-		options++;
-	}
-
-	if (greh->flags & GRE_KEY) {
-		tpi->key = *options;
-		options++;
-	} else {
-		tpi->key = 0;
-	}
-	if (unlikely(greh->flags & GRE_SEQ)) {
-		tpi->seq = *options;
-		options++;
-	} else {
-		tpi->seq = 0;
-	}
-	/* WCCP version 1 and 2 protocol decoding.
-	 * - Change protocol to IP
-	 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
-	 */
-	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
-		tpi->proto = htons(ETH_P_IP);
-		if ((*(u8 *)options & 0xF0) != 0x40) {
-			hdr_len += 4;
-			if (!pskb_may_pull(skb, hdr_len))
-				return -EINVAL;
-		}
-	}
-	return iptunnel_pull_header(skb, hdr_len, tpi->proto, false);
-}
-
 static void ipgre_err(struct sk_buff *skb, u32 info,
 		      const struct tnl_ptk_info *tpi)
 {
@@ -340,12 +221,16 @@ static void gre_err(struct sk_buff *skb, u32 info)
 	const int code = icmp_hdr(skb)->code;
 	struct tnl_ptk_info tpi;
 	bool csum_err = false;
+	int hdr_len;
 
-	if (parse_gre_header(skb, &tpi, &csum_err)) {
+	if (gre_parse_header(skb, &tpi, &csum_err, &hdr_len)) {
 		if (!csum_err)		/* ignore csum errors. */
 			return;
 	}
 
+	if (iptunnel_pull_header(skb, hdr_len, tpi.proto, false))
+		return;
+
 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 				 skb->dev->ifindex, 0, IPPROTO_GRE, 0);
@@ -419,6 +304,7 @@ static int gre_rcv(struct sk_buff *skb)
 {
 	struct tnl_ptk_info tpi;
 	bool csum_err = false;
+	int hdr_len;
 
 #ifdef CONFIG_NET_IPGRE_BROADCAST
 	if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
@@ -428,7 +314,10 @@ static int gre_rcv(struct sk_buff *skb)
 	}
 #endif
 
-	if (parse_gre_header(skb, &tpi, &csum_err) < 0)
+	if (gre_parse_header(skb, &tpi, &csum_err, &hdr_len) < 0)
+		goto drop;
+
+	if (iptunnel_pull_header(skb, hdr_len, tpi.proto, false))
 		goto drop;
 
 	if (ipgre_rcv(skb, &tpi) == PACKET_RCVD)
@@ -460,7 +349,7 @@ static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,
 
 	skb_reset_transport_header(skb);
 	greh = (struct gre_base_hdr *)skb->data;
-	greh->flags = tnl_flags_to_gre_flags(flags);
+	greh->flags = gre_tnl_flags_to_gre_flags(flags);
 	greh->protocol = proto;
 
 	if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
@@ -552,7 +441,7 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 					  fl.saddr);
 	}
 
-	tunnel_hlen = ip_gre_calc_hlen(key->tun_flags);
+	tunnel_hlen = gre_calc_hlen(key->tun_flags);
 
 	min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
 			+ tunnel_hlen + sizeof(struct iphdr);
@@ -694,8 +583,8 @@ static int ipgre_tunnel_ioctl(struct net_device *dev,
 	if (err)
 		return err;
 
-	p.i_flags = tnl_flags_to_gre_flags(p.i_flags);
-	p.o_flags = tnl_flags_to_gre_flags(p.o_flags);
+	p.i_flags = gre_tnl_flags_to_gre_flags(p.i_flags);
+	p.o_flags = gre_tnl_flags_to_gre_flags(p.o_flags);
 
 	if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 		return -EFAULT;
@@ -739,7 +628,7 @@ static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
 
 	iph = (struct iphdr *)skb_push(skb, t->hlen + sizeof(*iph));
 	greh = (struct gre_base_hdr *)(iph+1);
-	greh->flags = tnl_flags_to_gre_flags(t->parms.o_flags);
+	greh->flags = gre_tnl_flags_to_gre_flags(t->parms.o_flags);
 	greh->protocol = htons(type);
 
 	memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
@@ -840,7 +729,7 @@ static void __gre_tunnel_init(struct net_device *dev)
 	int t_hlen;
 
 	tunnel = netdev_priv(dev);
-	tunnel->tun_hlen = ip_gre_calc_hlen(tunnel->parms.o_flags);
+	tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
 	tunnel->parms.iph.protocol = IPPROTO_GRE;
 
 	tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
@@ -1155,8 +1044,10 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	struct ip_tunnel_parm *p = &t->parms;
 
 	if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
-	    nla_put_be16(skb, IFLA_GRE_IFLAGS, tnl_flags_to_gre_flags(p->i_flags)) ||
-	    nla_put_be16(skb, IFLA_GRE_OFLAGS, tnl_flags_to_gre_flags(p->o_flags)) ||
+	    nla_put_be16(skb, IFLA_GRE_IFLAGS,
+			 gre_tnl_flags_to_gre_flags(p->i_flags)) ||
+	    nla_put_be16(skb, IFLA_GRE_OFLAGS,
+			 gre_tnl_flags_to_gre_flags(p->o_flags)) ||
 	    nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
 	    nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
 	    nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||

From 308edfdf1563f78e93ebda9aee608279de1c5898 Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Fri, 29 Apr 2016 17:12:17 -0700
Subject: [PATCH 3/7] gre6: Cleanup GREv6 receive path, call common GRE
 functions

- Create gre_rcv function. This calls gre_parse_header and ip6gre_rcv.
  - Call ip6_tnl_rcv. Doing this and using gre_parse_header eliminates
    most of the code in ip6gre_rcv.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/ip6_gre.c | 140 ++++++++-------------------------------------
 1 file changed, 23 insertions(+), 117 deletions(-)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index ca5a2c5675c5c..9b33745761ca7 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -54,6 +54,7 @@
 #include <net/ip6_fib.h>
 #include <net/ip6_route.h>
 #include <net/ip6_tunnel.h>
+#include <net/gre.h>
 
 
 static bool log_ecn_error = true;
@@ -443,137 +444,40 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	t->err_time = jiffies;
 }
 
-static int ip6gre_rcv(struct sk_buff *skb)
+static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
 {
 	const struct ipv6hdr *ipv6h;
-	u8     *h;
-	__be16    flags;
-	__sum16   csum = 0;
-	__be32 key = 0;
-	u32    seqno = 0;
 	struct ip6_tnl *tunnel;
-	int    offset = 4;
-	__be16 gre_proto;
-	int err;
-
-	if (!pskb_may_pull(skb, sizeof(struct in6_addr)))
-		goto drop;
 
 	ipv6h = ipv6_hdr(skb);
-	h = skb->data;
-	flags = *(__be16 *)h;
-
-	if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
-		/* - Version must be 0.
-		   - We do not support routing headers.
-		 */
-		if (flags&(GRE_VERSION|GRE_ROUTING))
-			goto drop;
-
-		if (flags&GRE_CSUM) {
-			csum = skb_checksum_simple_validate(skb);
-			offset += 4;
-		}
-		if (flags&GRE_KEY) {
-			key = *(__be32 *)(h + offset);
-			offset += 4;
-		}
-		if (flags&GRE_SEQ) {
-			seqno = ntohl(*(__be32 *)(h + offset));
-			offset += 4;
-		}
-	}
-
-	gre_proto = *(__be16 *)(h + 2);
-
 	tunnel = ip6gre_tunnel_lookup(skb->dev,
-					  &ipv6h->saddr, &ipv6h->daddr, key,
-					  gre_proto);
+				      &ipv6h->saddr, &ipv6h->daddr, tpi->key,
+				      tpi->proto);
 	if (tunnel) {
-		struct pcpu_sw_netstats *tstats;
-
-		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
-			goto drop;
-
-		if (!ip6_tnl_rcv_ctl(tunnel, &ipv6h->daddr, &ipv6h->saddr)) {
-			tunnel->dev->stats.rx_dropped++;
-			goto drop;
-		}
-
-		skb->protocol = gre_proto;
-		/* WCCP version 1 and 2 protocol decoding.
-		 * - Change protocol to IPv6
-		 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
-		 */
-		if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
-			skb->protocol = htons(ETH_P_IPV6);
-			if ((*(h + offset) & 0xF0) != 0x40)
-				offset += 4;
-		}
+		ip6_tnl_rcv(tunnel, skb, tpi, NULL, false);
 
-		skb->mac_header = skb->network_header;
-		__pskb_pull(skb, offset);
-		skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
-
-		if (((flags&GRE_CSUM) && csum) ||
-		    (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
-			tunnel->dev->stats.rx_crc_errors++;
-			tunnel->dev->stats.rx_errors++;
-			goto drop;
-		}
-		if (tunnel->parms.i_flags&GRE_SEQ) {
-			if (!(flags&GRE_SEQ) ||
-			    (tunnel->i_seqno &&
-					(s32)(seqno - tunnel->i_seqno) < 0)) {
-				tunnel->dev->stats.rx_fifo_errors++;
-				tunnel->dev->stats.rx_errors++;
-				goto drop;
-			}
-			tunnel->i_seqno = seqno + 1;
-		}
-
-		/* Warning: All skb pointers will be invalidated! */
-		if (tunnel->dev->type == ARPHRD_ETHER) {
-			if (!pskb_may_pull(skb, ETH_HLEN)) {
-				tunnel->dev->stats.rx_length_errors++;
-				tunnel->dev->stats.rx_errors++;
-				goto drop;
-			}
-
-			ipv6h = ipv6_hdr(skb);
-			skb->protocol = eth_type_trans(skb, tunnel->dev);
-			skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
-		}
-
-		__skb_tunnel_rx(skb, tunnel->dev, tunnel->net);
+		return PACKET_RCVD;
+	}
 
-		skb_reset_network_header(skb);
+	return PACKET_REJECT;
+}
 
-		err = IP6_ECN_decapsulate(ipv6h, skb);
-		if (unlikely(err)) {
-			if (log_ecn_error)
-				net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
-						     &ipv6h->saddr,
-						     ipv6_get_dsfield(ipv6h));
-			if (err > 1) {
-				++tunnel->dev->stats.rx_frame_errors;
-				++tunnel->dev->stats.rx_errors;
-				goto drop;
-			}
-		}
+static int gre_rcv(struct sk_buff *skb)
+{
+	struct tnl_ptk_info tpi;
+	bool csum_err = false;
+	int hdr_len;
 
-		tstats = this_cpu_ptr(tunnel->dev->tstats);
-		u64_stats_update_begin(&tstats->syncp);
-		tstats->rx_packets++;
-		tstats->rx_bytes += skb->len;
-		u64_stats_update_end(&tstats->syncp);
+	if (gre_parse_header(skb, &tpi, &csum_err, &hdr_len) < 0)
+		goto drop;
 
-		netif_rx(skb);
+	if (iptunnel_pull_header(skb, hdr_len, tpi.proto, false))
+		goto drop;
 
+	if (ip6gre_rcv(skb, &tpi) == PACKET_RCVD)
 		return 0;
-	}
-	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 
+	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 drop:
 	kfree_skb(skb);
 	return 0;
@@ -1075,6 +979,8 @@ static int ip6gre_tunnel_ioctl(struct net_device *dev,
 	struct net *net = t->net;
 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
 
+	memset(&p1, 0, sizeof(p1));
+
 	switch (cmd) {
 	case SIOCGETTUNNEL:
 		if (dev == ign->fb_tunnel_dev) {
@@ -1318,7 +1224,7 @@ static void ip6gre_fb_tunnel_init(struct net_device *dev)
 
 
 static struct inet6_protocol ip6gre_protocol __read_mostly = {
-	.handler     = ip6gre_rcv,
+	.handler     = gre_rcv,
 	.err_handler = ip6gre_err,
 	.flags       = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 };

From 8eb30be0352d09165e94a41fef1c7b994dca0714 Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Fri, 29 Apr 2016 17:12:18 -0700
Subject: [PATCH 4/7] ipv6: Create ip6_tnl_xmit

This patch renames ip6_tnl_xmit2 to ip6_tnl_xmit and exports it. Other
users like GRE will be able to call this. The original ip6_tnl_xmit
function is renamed to ip6_tnl_start_xmit (this is an ndo_start_xmit
function).

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/ip6_tunnel.h |  2 ++
 net/ipv6/ip6_tunnel.c    | 47 +++++++++++++++++++++++++---------------
 2 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h
index eab3a9b19ae09..835491bd56365 100644
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -69,6 +69,8 @@ int ip6_tnl_rcv(struct ip6_tnl *tunnel, struct sk_buff *skb,
 		bool log_ecn_error);
 int ip6_tnl_xmit_ctl(struct ip6_tnl *t, const struct in6_addr *laddr,
 		     const struct in6_addr *raddr);
+int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
+		 struct flowi6 *fl6, int encap_limit, __u32 *pmtu, __u8 proto);
 __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw);
 __u32 ip6_tnl_get_cap(struct ip6_tnl *t, const struct in6_addr *laddr,
 			     const struct in6_addr *raddr);
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 94ed065eff7f3..b1f31d2b17cd4 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -979,13 +979,14 @@ int ip6_tnl_xmit_ctl(struct ip6_tnl *t,
 EXPORT_SYMBOL_GPL(ip6_tnl_xmit_ctl);
 
 /**
- * ip6_tnl_xmit2 - encapsulate packet and send
+ * ip6_tnl_xmit - encapsulate packet and send
  *   @skb: the outgoing socket buffer
  *   @dev: the outgoing tunnel device
  *   @dsfield: dscp code for outer header
- *   @fl: flow of tunneled packet
+ *   @fl6: flow of tunneled packet
  *   @encap_limit: encapsulation limit
  *   @pmtu: Path MTU is stored if packet is too big
+ *   @proto: next header value
  *
  * Description:
  *   Build new header and do some sanity checks on the packet before sending
@@ -997,12 +998,9 @@ EXPORT_SYMBOL_GPL(ip6_tnl_xmit_ctl);
  *   %-EMSGSIZE message too big. return mtu in this case.
  **/
 
-static int ip6_tnl_xmit2(struct sk_buff *skb,
-			 struct net_device *dev,
-			 __u8 dsfield,
-			 struct flowi6 *fl6,
-			 int encap_limit,
-			 __u32 *pmtu)
+int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
+		 struct flowi6 *fl6, int encap_limit, __u32 *pmtu,
+		 __u8 proto)
 {
 	struct ip6_tnl *t = netdev_priv(dev);
 	struct net *net = t->net;
@@ -1013,7 +1011,6 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 	struct net_device *tdev;
 	int mtu;
 	unsigned int max_headroom = sizeof(struct ipv6hdr);
-	u8 proto;
 	int err = -1;
 
 	/* NBMA tunnel */
@@ -1075,12 +1072,23 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 		mtu = IPV6_MIN_MTU;
 	if (skb_dst(skb))
 		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
-	if (skb->len > mtu) {
+	if (skb->len > mtu && !skb_is_gso(skb)) {
 		*pmtu = mtu;
 		err = -EMSGSIZE;
 		goto tx_err_dst_release;
 	}
 
+	if (t->err_count > 0) {
+		if (time_before(jiffies,
+				t->err_time + IP6TUNNEL_ERR_TIMEO)) {
+			t->err_count--;
+
+			dst_link_failure(skb);
+		} else {
+			t->err_count = 0;
+		}
+	}
+
 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
 
 	/*
@@ -1108,7 +1116,6 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 
 	skb->transport_header = skb->network_header;
 
-	proto = fl6->flowi6_proto;
 	if (encap_limit >= 0) {
 		init_tel_txopt(&opt, encap_limit);
 		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
@@ -1119,6 +1126,11 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 		skb->encapsulation = 1;
 	}
 
+	max_headroom = LL_RESERVED_SPACE(dst->dev) + sizeof(struct ipv6hdr)
+			+ dst->header_len;
+	if (max_headroom > dev->needed_headroom)
+		dev->needed_headroom = max_headroom;
+
 	skb_push(skb, sizeof(struct ipv6hdr));
 	skb_reset_network_header(skb);
 	ipv6h = ipv6_hdr(skb);
@@ -1137,6 +1149,7 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 	dst_release(dst);
 	return err;
 }
+EXPORT_SYMBOL(ip6_tnl_xmit);
 
 static inline int
 ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -1160,7 +1173,6 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 		encap_limit = t->parms.encap_limit;
 
 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
-	fl6.flowi6_proto = IPPROTO_IPIP;
 
 	dsfield = ipv4_get_dsfield(iph);
 
@@ -1170,7 +1182,8 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
 		fl6.flowi6_mark = skb->mark;
 
-	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+	err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,
+			   IPPROTO_IPIP);
 	if (err != 0) {
 		/* XXX: send ICMP error even if DF is not set. */
 		if (err == -EMSGSIZE)
@@ -1214,7 +1227,6 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 		encap_limit = t->parms.encap_limit;
 
 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
-	fl6.flowi6_proto = IPPROTO_IPV6;
 
 	dsfield = ipv6_get_dsfield(ipv6h);
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
@@ -1224,7 +1236,8 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
 		fl6.flowi6_mark = skb->mark;
 
-	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+	err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,
+			   IPPROTO_IPV6);
 	if (err != 0) {
 		if (err == -EMSGSIZE)
 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
@@ -1235,7 +1248,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 }
 
 static netdev_tx_t
-ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
+ip6_tnl_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ip6_tnl *t = netdev_priv(dev);
 	struct net_device_stats *stats = &t->dev->stats;
@@ -1556,7 +1569,7 @@ EXPORT_SYMBOL(ip6_tnl_get_iflink);
 static const struct net_device_ops ip6_tnl_netdev_ops = {
 	.ndo_init	= ip6_tnl_dev_init,
 	.ndo_uninit	= ip6_tnl_dev_uninit,
-	.ndo_start_xmit = ip6_tnl_xmit,
+	.ndo_start_xmit = ip6_tnl_start_xmit,
 	.ndo_do_ioctl	= ip6_tnl_ioctl,
 	.ndo_change_mtu = ip6_tnl_change_mtu,
 	.ndo_get_stats	= ip6_get_stats,

From 182a352d2d5e0b435f7856c0cc23d467dcec55ef Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Fri, 29 Apr 2016 17:12:19 -0700
Subject: [PATCH 5/7] gre: Create common functions for transmit

Create common functions for both IPv4 and IPv6 GRE in transmit. These
are put into gre.h.

Common functions are for:
  - GRE checksum calculation. Move gre_checksum to gre.h.
  - Building a GRE header. Move GRE build_header and rename
    gre_build_header.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/gre.h | 44 +++++++++++++++++++++++++++++++++++++++
 net/ipv4/ip_gre.c | 52 +++++------------------------------------------
 2 files changed, 49 insertions(+), 47 deletions(-)

diff --git a/include/net/gre.h b/include/net/gre.h
index 39591584ec92b..29e37322c06ed 100644
--- a/include/net/gre.h
+++ b/include/net/gre.h
@@ -85,4 +85,48 @@ static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
 	return flags;
 }
 
+static inline __sum16 gre_checksum(struct sk_buff *skb)
+{
+	__wsum csum;
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL)
+		csum = lco_csum(skb);
+	else
+		csum = skb_checksum(skb, 0, skb->len, 0);
+	return csum_fold(csum);
+}
+
+static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
+				    __be16 flags, __be16 proto,
+				    __be32 key, __be32 seq)
+{
+	struct gre_base_hdr *greh;
+
+	skb_push(skb, hdr_len);
+
+	skb_reset_transport_header(skb);
+	greh = (struct gre_base_hdr *)skb->data;
+	greh->flags = gre_tnl_flags_to_gre_flags(flags);
+	greh->protocol = proto;
+
+	if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
+		__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
+
+		if (flags & TUNNEL_SEQ) {
+			*ptr = seq;
+			ptr--;
+		}
+		if (flags & TUNNEL_KEY) {
+			*ptr = key;
+			ptr--;
+		}
+		if (flags & TUNNEL_CSUM &&
+		    !(skb_shinfo(skb)->gso_type &
+		      (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
+			*ptr = 0;
+			*(__sum16 *)ptr = gre_checksum(skb);
+		}
+	}
+}
+
 #endif
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index f6db3d6a4d4da..2480d79b0e379 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -329,49 +329,6 @@ static int gre_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static __sum16 gre_checksum(struct sk_buff *skb)
-{
-	__wsum csum;
-
-	if (skb->ip_summed == CHECKSUM_PARTIAL)
-		csum = lco_csum(skb);
-	else
-		csum = skb_checksum(skb, 0, skb->len, 0);
-	return csum_fold(csum);
-}
-
-static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,
-			 __be16 proto, __be32 key, __be32 seq)
-{
-	struct gre_base_hdr *greh;
-
-	skb_push(skb, hdr_len);
-
-	skb_reset_transport_header(skb);
-	greh = (struct gre_base_hdr *)skb->data;
-	greh->flags = gre_tnl_flags_to_gre_flags(flags);
-	greh->protocol = proto;
-
-	if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
-		__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
-
-		if (flags & TUNNEL_SEQ) {
-			*ptr = seq;
-			ptr--;
-		}
-		if (flags & TUNNEL_KEY) {
-			*ptr = key;
-			ptr--;
-		}
-		if (flags & TUNNEL_CSUM &&
-		    !(skb_shinfo(skb)->gso_type &
-		      (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
-			*ptr = 0;
-			*(__sum16 *)ptr = gre_checksum(skb);
-		}
-	}
-}
-
 static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 		       const struct iphdr *tnl_params,
 		       __be16 proto)
@@ -382,8 +339,9 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 		tunnel->o_seqno++;
 
 	/* Push GRE header. */
-	build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,
-		     proto, tunnel->parms.o_key, htonl(tunnel->o_seqno));
+	gre_build_header(skb, tunnel->tun_hlen,
+			 tunnel->parms.o_flags, proto, tunnel->parms.o_key,
+			 htonl(tunnel->o_seqno));
 
 	skb_set_inner_protocol(skb, proto);
 	ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
@@ -460,8 +418,8 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto err_free_rt;
 
 	flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
-	build_header(skb, tunnel_hlen, flags, htons(ETH_P_TEB),
-		     tunnel_id_to_key(tun_info->key.tun_id), 0);
+	gre_build_header(skb, tunnel_hlen, flags, htons(ETH_P_TEB),
+			 tunnel_id_to_key(tun_info->key.tun_id), 0);
 
 	df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;
 

From 79ecb90e65f33d1941ac1f8e43eec34ec3bdbad8 Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Fri, 29 Apr 2016 17:12:20 -0700
Subject: [PATCH 6/7] ipv6: Generic tunnel cleanup

A few generic changes to generalize tunnels in IPv6:
  - Export ip6_tnl_change_mtu so that it can be called by ip6_gre
  - Add tun_hlen to ip6_tnl structure.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/ip6_tunnel.h | 5 ++++-
 net/ipv6/ip6_tunnel.c    | 7 +++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h
index 835491bd56365..fb9e0153f4f24 100644
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -50,8 +50,10 @@ struct ip6_tnl {
 	/* These fields used only by GRE */
 	__u32 i_seqno;	/* The last seen seqno	*/
 	__u32 o_seqno;	/* The last output seqno */
-	int hlen;       /* Precalculated GRE header length */
+	int hlen;       /* tun_hlen + encap_hlen */
+	int tun_hlen;	/* Precalculated header length */
 	int mlink;
+
 };
 
 /* Tunnel encapsulation limit destination sub-option */
@@ -76,6 +78,7 @@ __u32 ip6_tnl_get_cap(struct ip6_tnl *t, const struct in6_addr *laddr,
 			     const struct in6_addr *raddr);
 struct net *ip6_tnl_get_link_net(const struct net_device *dev);
 int ip6_tnl_get_iflink(const struct net_device *dev);
+int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu);
 
 #ifdef CONFIG_INET
 static inline void ip6tunnel_xmit(struct sock *sk, struct sk_buff *skb,
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index b1f31d2b17cd4..ade55af6ace6b 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1540,8 +1540,7 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
  *   %-EINVAL if mtu too small
  **/
 
-static int
-ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
+int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct ip6_tnl *tnl = netdev_priv(dev);
 
@@ -1557,6 +1556,7 @@ ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
 	dev->mtu = new_mtu;
 	return 0;
 }
+EXPORT_SYMBOL(ip6_tnl_change_mtu);
 
 int ip6_tnl_get_iflink(const struct net_device *dev)
 {
@@ -1632,6 +1632,9 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
 	if (ret)
 		goto destroy_dst;
 
+	t->hlen = 0;
+	t->tun_hlen = 0;
+
 	return 0;
 
 destroy_dst:

From b05229f442288210f2b1f5b4b2a9d71836e90686 Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Fri, 29 Apr 2016 17:12:21 -0700
Subject: [PATCH 7/7] gre6: Cleanup GREv6 transmit path, call common GRE
 functions

Changes in GREv6 transmit path:
  - Call gre_checksum, remove gre6_checksum
  - Rename ip6gre_xmit2 to __gre6_xmit
  - Call gre_build_header utility function
  - Call ip6_tnl_xmit common function
  - Call ip6_tnl_change_mtu, eliminate ip6gre_tunnel_change_mtu

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/ip6_gre.c | 252 +++++++++------------------------------------
 1 file changed, 50 insertions(+), 202 deletions(-)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 9b33745761ca7..10127741a60db 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -488,199 +488,40 @@ struct ipv6_tel_txoption {
 	__u8 dst_opt[8];
 };
 
-static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
+static int gre_handle_offloads(struct sk_buff *skb, bool csum)
 {
-	memset(opt, 0, sizeof(struct ipv6_tel_txoption));
-
-	opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
-	opt->dst_opt[3] = 1;
-	opt->dst_opt[4] = encap_limit;
-	opt->dst_opt[5] = IPV6_TLV_PADN;
-	opt->dst_opt[6] = 1;
-
-	opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
-	opt->ops.opt_nflen = 8;
+	return iptunnel_handle_offloads(skb,
+					csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
 }
 
-static __sum16 gre6_checksum(struct sk_buff *skb)
-{
-	__wsum csum;
-
-	if (skb->ip_summed == CHECKSUM_PARTIAL)
-		csum = lco_csum(skb);
-	else
-		csum = skb_checksum(skb, sizeof(struct ipv6hdr),
-				    skb->len - sizeof(struct ipv6hdr), 0);
-	return csum_fold(csum);
-}
-
-static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
-			 struct net_device *dev,
-			 __u8 dsfield,
-			 struct flowi6 *fl6,
-			 int encap_limit,
-			 __u32 *pmtu)
+static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
+			       struct net_device *dev, __u8 dsfield,
+			       struct flowi6 *fl6, int encap_limit,
+			       __u32 *pmtu, __be16 proto)
 {
 	struct ip6_tnl *tunnel = netdev_priv(dev);
-	struct net *net = tunnel->net;
-	struct net_device *tdev;    /* Device to other host */
-	struct ipv6hdr  *ipv6h;     /* Our new IP header */
-	unsigned int min_headroom = 0; /* The extra header space needed */
-	int    gre_hlen;
-	struct ipv6_tel_txoption opt;
-	int    mtu;
-	struct dst_entry *dst = NULL, *ndst = NULL;
-	struct net_device_stats *stats = &tunnel->dev->stats;
-	int err = -1;
-	u8 proto;
-	__be16 protocol;
+	__be16 protocol = (dev->type == ARPHRD_ETHER) ?
+			  htons(ETH_P_TEB) : proto;
 
 	if (dev->type == ARPHRD_ETHER)
 		IPCB(skb)->flags = 0;
 
-	if (dev->header_ops && dev->type == ARPHRD_IP6GRE) {
-		gre_hlen = 0;
-		ipv6h = (struct ipv6hdr *)skb->data;
-		fl6->daddr = ipv6h->daddr;
-	} else {
-		gre_hlen = tunnel->hlen;
+	if (dev->header_ops && dev->type == ARPHRD_IP6GRE)
+		fl6->daddr = ((struct ipv6hdr *)skb->data)->daddr;
+	else
 		fl6->daddr = tunnel->parms.raddr;
-	}
-
-	if (!fl6->flowi6_mark)
-		dst = dst_cache_get(&tunnel->dst_cache);
-
-	if (!dst) {
-		dst = ip6_route_output(net, NULL, fl6);
-
-		if (dst->error)
-			goto tx_err_link_failure;
-		dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), NULL, 0);
-		if (IS_ERR(dst)) {
-			err = PTR_ERR(dst);
-			dst = NULL;
-			goto tx_err_link_failure;
-		}
-		ndst = dst;
-	}
-
-	tdev = dst->dev;
-
-	if (tdev == dev) {
-		stats->collisions++;
-		net_warn_ratelimited("%s: Local routing loop detected!\n",
-				     tunnel->parms.name);
-		goto tx_err_dst_release;
-	}
 
-	mtu = dst_mtu(dst) - sizeof(*ipv6h);
-	if (encap_limit >= 0) {
-		min_headroom += 8;
-		mtu -= 8;
-	}
-	if (mtu < IPV6_MIN_MTU)
-		mtu = IPV6_MIN_MTU;
-	if (skb_dst(skb))
-		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
-	if (skb->len > mtu && !skb_is_gso(skb)) {
-		*pmtu = mtu;
-		err = -EMSGSIZE;
-		goto tx_err_dst_release;
-	}
+	if (tunnel->parms.o_flags & TUNNEL_SEQ)
+		tunnel->o_seqno++;
 
-	if (tunnel->err_count > 0) {
-		if (time_before(jiffies,
-				tunnel->err_time + IP6TUNNEL_ERR_TIMEO)) {
-			tunnel->err_count--;
+	/* Push GRE header. */
+	gre_build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,
+			 protocol, tunnel->parms.o_key, htonl(tunnel->o_seqno));
 
-			dst_link_failure(skb);
-		} else
-			tunnel->err_count = 0;
-	}
+	skb_set_inner_protocol(skb, proto);
 
-	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
-
-	min_headroom += LL_RESERVED_SPACE(tdev) + gre_hlen + dst->header_len;
-
-	if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
-		int head_delta = SKB_DATA_ALIGN(min_headroom -
-						skb_headroom(skb) +
-						16);
-
-		err = pskb_expand_head(skb, max_t(int, head_delta, 0),
-				       0, GFP_ATOMIC);
-		if (min_headroom > dev->needed_headroom)
-			dev->needed_headroom = min_headroom;
-		if (unlikely(err))
-			goto tx_err_dst_release;
-	}
-
-	if (!fl6->flowi6_mark && ndst)
-		dst_cache_set_ip6(&tunnel->dst_cache, ndst, &fl6->saddr);
-	skb_dst_set(skb, dst);
-
-	proto = NEXTHDR_GRE;
-	if (encap_limit >= 0) {
-		init_tel_txopt(&opt, encap_limit);
-		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
-	}
-
-	err = iptunnel_handle_offloads(skb,
-				       (tunnel->parms.o_flags & GRE_CSUM) ?
-				       SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
-	if (err)
-		goto tx_err_dst_release;
-
-	skb_push(skb, gre_hlen);
-	skb_reset_network_header(skb);
-	skb_set_transport_header(skb, sizeof(*ipv6h));
-
-	/*
-	 *	Push down and install the IP header.
-	 */
-	ipv6h = ipv6_hdr(skb);
-	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
-		     ip6_make_flowlabel(net, skb, fl6->flowlabel, true, fl6));
-	ipv6h->hop_limit = tunnel->parms.hop_limit;
-	ipv6h->nexthdr = proto;
-	ipv6h->saddr = fl6->saddr;
-	ipv6h->daddr = fl6->daddr;
-
-	((__be16 *)(ipv6h + 1))[0] = tunnel->parms.o_flags;
-	protocol = (dev->type == ARPHRD_ETHER) ?
-		    htons(ETH_P_TEB) : skb->protocol;
-	((__be16 *)(ipv6h + 1))[1] = protocol;
-
-	if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
-		__be32 *ptr = (__be32 *)(((u8 *)ipv6h) + tunnel->hlen - 4);
-
-		if (tunnel->parms.o_flags&GRE_SEQ) {
-			++tunnel->o_seqno;
-			*ptr = htonl(tunnel->o_seqno);
-			ptr--;
-		}
-		if (tunnel->parms.o_flags&GRE_KEY) {
-			*ptr = tunnel->parms.o_key;
-			ptr--;
-		}
-		if ((tunnel->parms.o_flags & GRE_CSUM) &&
-		    !(skb_shinfo(skb)->gso_type &
-		      (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
-			*ptr = 0;
-			*(__sum16 *)ptr = gre6_checksum(skb);
-		}
-	}
-
-	skb_set_inner_protocol(skb, protocol);
-
-	ip6tunnel_xmit(NULL, skb, dev);
-	return 0;
-tx_err_link_failure:
-	stats->tx_carrier_errors++;
-	dst_link_failure(skb);
-tx_err_dst_release:
-	dst_release(dst);
-	return err;
+	return ip6_tnl_xmit(skb, dev, dsfield, fl6, encap_limit, pmtu,
+			    NEXTHDR_GRE);
 }
 
 static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
@@ -699,7 +540,6 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
 		encap_limit = t->parms.encap_limit;
 
 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
-	fl6.flowi6_proto = IPPROTO_GRE;
 
 	dsfield = ipv4_get_dsfield(iph);
 
@@ -709,7 +549,12 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
 		fl6.flowi6_mark = skb->mark;
 
-	err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+	err = gre_handle_offloads(skb, !!(t->parms.o_flags & TUNNEL_CSUM));
+	if (err)
+		return -1;
+
+	err = __gre6_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,
+			  skb->protocol);
 	if (err != 0) {
 		/* XXX: send ICMP error even if DF is not set. */
 		if (err == -EMSGSIZE)
@@ -749,7 +594,6 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev)
 		encap_limit = t->parms.encap_limit;
 
 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
-	fl6.flowi6_proto = IPPROTO_GRE;
 
 	dsfield = ipv6_get_dsfield(ipv6h);
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
@@ -759,7 +603,11 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev)
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
 		fl6.flowi6_mark = skb->mark;
 
-	err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+	if (gre_handle_offloads(skb, !!(t->parms.o_flags & TUNNEL_CSUM)))
+		return -1;
+
+	err = __gre6_xmit(skb, dev, dsfield, &fl6, encap_limit,
+			  &mtu, skb->protocol);
 	if (err != 0) {
 		if (err == -EMSGSIZE)
 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
@@ -803,7 +651,11 @@ static int ip6gre_xmit_other(struct sk_buff *skb, struct net_device *dev)
 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
 	fl6.flowi6_proto = skb->protocol;
 
-	err = ip6gre_xmit2(skb, dev, 0, &fl6, encap_limit, &mtu);
+	err = gre_handle_offloads(skb, !!(t->parms.o_flags & TUNNEL_CSUM));
+	if (err)
+		return err;
+
+	err = __gre6_xmit(skb, dev, 0, &fl6, encap_limit, &mtu, skb->protocol);
 
 	return err;
 }
@@ -1080,15 +932,6 @@ static int ip6gre_tunnel_ioctl(struct net_device *dev,
 	return err;
 }
 
-static int ip6gre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
-{
-	if (new_mtu < 68 ||
-	    new_mtu > 0xFFF8 - dev->hard_header_len)
-		return -EINVAL;
-	dev->mtu = new_mtu;
-	return 0;
-}
-
 static int ip6gre_header(struct sk_buff *skb, struct net_device *dev,
 			unsigned short type,
 			const void *daddr, const void *saddr, unsigned int len)
@@ -1132,7 +975,7 @@ static const struct net_device_ops ip6gre_netdev_ops = {
 	.ndo_uninit		= ip6gre_tunnel_uninit,
 	.ndo_start_xmit		= ip6gre_tunnel_xmit,
 	.ndo_do_ioctl		= ip6gre_tunnel_ioctl,
-	.ndo_change_mtu		= ip6gre_tunnel_change_mtu,
+	.ndo_change_mtu		= ip6_tnl_change_mtu,
 	.ndo_get_stats64	= ip_tunnel_get_stats64,
 	.ndo_get_iflink		= ip6_tnl_get_iflink,
 };
@@ -1148,17 +991,11 @@ static void ip6gre_dev_free(struct net_device *dev)
 
 static void ip6gre_tunnel_setup(struct net_device *dev)
 {
-	struct ip6_tnl *t;
-
 	dev->netdev_ops = &ip6gre_netdev_ops;
 	dev->destructor = ip6gre_dev_free;
 
 	dev->type = ARPHRD_IP6GRE;
-	dev->hard_header_len = LL_MAX_HEADER + sizeof(struct ipv6hdr) + 4;
-	dev->mtu = ETH_DATA_LEN - sizeof(struct ipv6hdr) - 4;
-	t = netdev_priv(dev);
-	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
-		dev->mtu -= 8;
+
 	dev->flags |= IFF_NOARP;
 	dev->addr_len = sizeof(struct in6_addr);
 	netif_keep_dst(dev);
@@ -1168,6 +1005,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
 {
 	struct ip6_tnl *tunnel;
 	int ret;
+	int t_hlen;
 
 	tunnel = netdev_priv(dev);
 
@@ -1186,6 +1024,16 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
 		return ret;
 	}
 
+	tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
+
+	t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
+
+	dev->needed_headroom	= LL_MAX_HEADER + t_hlen + 4;
+	dev->mtu		= ETH_DATA_LEN - t_hlen - 4;
+
+	if (!(tunnel->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
+		dev->mtu -= 8;
+
 	return 0;
 }
 
@@ -1420,7 +1268,7 @@ static const struct net_device_ops ip6gre_tap_netdev_ops = {
 	.ndo_start_xmit = ip6gre_tunnel_xmit,
 	.ndo_set_mac_address = eth_mac_addr,
 	.ndo_validate_addr = eth_validate_addr,
-	.ndo_change_mtu = ip6gre_tunnel_change_mtu,
+	.ndo_change_mtu = ip6_tnl_change_mtu,
 	.ndo_get_stats64 = ip_tunnel_get_stats64,
 	.ndo_get_iflink = ip6_tnl_get_iflink,
 };